<!--
 * @Description: 尺寸
 * @Author: rendc
 * @Date: 2021-08-06 14:21:36
 * @LastEditors: rendc
 * @LastEditTime: 2021-08-06 16:43:23
-->
<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>尺寸</title>
  <style>
    /* .app {
      font-size: 20px;
      padding: 2em;
    } */
    .app {
      background-color: tomato;
      width: 50%;
      font-size: 20px;
      padding: 1rem;
    }
  </style>
</head>

<body>
  <div class="app">
    mydiv
    <p id="myP" class="myPClass">
      我们的祖国是花园。
      <br>
      我们的祖国是花园。
    </p>
  </div>

</body>

</html>